Hi Doug,
the question of creating a Skin with two (or even more) Menus relies not on whether the skin is using Tables or not.
The key is the dnn:NAV provider
I selected for a Site of one of my customers the following Solution:
Main Menu (horizontal on Top of the Page)
<dnn:NAV ID="MainMenu" runat="server" ControlOrientation="horizontal" ExpandDepth="1"/>
SubMenu (vertical on the Left of the Page)
<dnn:NAV ID="SubMenu" runat="server" ControlOrientation="vertical" Level="child"/>
This gives you the desired two menu Style
I put that into extreme by adding even a third Menu on the right side of the Skin
<dnn:NAV ID="ThirdMenu" runat="server" ControlOrientation="vertical" Level="child" StartTabId="xxx"/>
This makes you Skin a little unflexible though, because the StartTabId has to be defined upfront of Creating the Skin itself. Means the Site Structure has to be finalized upfront.